When I beheld the extraordinarily vivid green lower Manzana Creek waters in late June, it felt truly hallucinogenic and reminded me of visions I’d had ingesting LSD (stupidly) back in my late 1960s undergrad days.
While hiking the wild and scenic Manzana again at the end of November, I saw that the intense emerald color had faded, yet most of the reduced pools remained tinged with a much stronger green color than usual.
The Manzana Creek Trail (30W13) reveals varied and fascinating seasonal details, such as a plethora of centipedes, serpents and compelling vistas along with wild turkeys marching along the road driving in.
A few readers of my June column wondered if I had jacked-up (enhanced) the vivid green color of the lower Manzana Creek in my lead photograph (reproduced here as the lead photograph). No, indeed.
Trekking pals wild Pete, Mr. C and I debated whether the iridescent green coloration was caused by extreme algae growth. While one favored pollution, except for atmospheric pollution there simply aren’t any factories or human habitation or virtually any human activities in this area of the pristine San Rafael Wilderness (two private inholdings are miles downstream from these two photographs).
I’m not a trained biologist, so Mr. C recently forwarded an explanation for that vivid green and sometimes smelly “filamentous algae” we detected from above when hiking the Potrero Trail in June.
Algae blooms are not uncommon, of course, e.g., in Arroyo Hondo Creek, but in frequenting these backcountry trails since 1973, I had never observed such a chromatic display. Reading about “A Slimy Summer: Algae” in the Land Trust for Santa Barbara County’s fall newsletter, I learned that there are at least four causes for this emerald bloom.
Algal growth — a very important part of aquatic food webs — often increases after wildfires. Nutrients including ash and sediments flow into the stream after fires, and these enhance algae growth. However, this mainly explains the algal growth in the Santa Barbara frontcountry, e.g. in Arroyo Hondo Creek.
The loss of trees and brush near creeks like the Manzana exposes the water to more sunlight. The Santa Barbara backcountry generally received at least twice the normal amount of rainfall last winter, and from the lead photograph I can discern how “naked” the Manzana’s whitened-stone streambed has become.
The many tall willows are mostly gone, swept away just like some of the smaller sycamores. More precious rays from Father Sol increases algal growth.
Above-average winter rains like we enjoyed last winter flush invertebrates from the riparian system, which requires considerable time for the full diversity of these “grazers” to make their comeback.
Tiny arthropods such as spiders, mites, various insects and crustaceans nibble away on the nutritious algae, but it takes time for them to return to action after the heavy natural flooding last winter. These organisms bring the system back into balance. The much lighter green in the late November photograph shows these critters have been hard at work.
The fourth cause also springs out of the truly heavy rainfall of last winter. In my 51 years of hiking up and down the Manzana, there usually have been extended periods in the later summer and fall when the creek disappears completely underground.
In most years, there would have been long, dry stretches of the glorious Manzana with no algae at all. Hiking up and down the Manzana recently, I’ve observed far more water flowing, and for a much longer period of time (the entire year), and this stimulates continuous reproduction and growth of green filamentous algae.
While moving around outside in our backcountry, I’ve also noted an increase in centipedes, renewed insect life and the rebounding dense chaparral that makes up 90% of the San Rafael Wilderness. What also follows is the point that overnight camping at either Nira or Davy Brown is quite pleasant with the nearby Manzana flowing. That is often not the case in late summer and fall.
Thus, it was surprising that on Nov. 27 there wasn’t a single car at Nira (a large camp with space for 30 cars), or parked at the nearby trailhead for backpackers heading downstream. When I drove into exquisite Davy Brown Camp, there also were no humans there!
The algal growth is quite abundant; the same stream flows through both camps mentioned, and official fire restrictions still do allow for open campfires in specific camps, including Nira and Davy Brown.
Do you want some solitude away from the hurly-burly of town and the rising crescendo of wars and political chaos? Freedom from the air-conditioned nightmare, as Henry Miller termed it? Then grab your children and friends, drive the 45 miles to Nira, take a deep sigh, kit up and amble along the green watercourse. On a warmer day, dip into the rejuvenating stream and appreciate the algae.
4.1.1.
Driving to Davy Brown/Nira both beside Manzana Creek: On Highway 101, take the Chumash Highway (154) past Lake Cachuma to Armour Ranch Road at the Santa Ynez River concrete bridge and turn right. After a mile, turn right again on Happy Canyon Road and drive right to the end at Nira Camp. I recommend forsaking electronics, and my friends’ cellphones could not get coverage along the Manzana.
Click here for my late June column with more information.
